Зображення сторінки
PDF
ePub

the average line shaft consumes from 20 to 30 per cent. of the power delivered to it in journal friction, if any number of hangers are used, or if the shaft is not absolutely aligned, it will be apparent that the use of individual motor drive will reduce this power loss appreciably. When only two or three machines are to be driven, it is, of course, more profitable to drive these from a short length of shafting than it would be to provide a separate motor

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors]

Fig. 21.-Form of Lathe Adapted for Direct Drive from Electric Motor.

for each machine tool, as one motor may be made to serve them all where the power requirements are not great.

The writer does not mean to imply that the internal combustion motor in its various stationary forms is not adapted for power delivery in small units, because many repair shops, some having a very complete equipment, obtain their power directly from an oil engine which is the most economical of the various power-generating units. When a generating set is used it is necessary to use an engine of greater power than would be needed if belted directly to the shaft line, but as in most installations

[blocks in formation]

Fig. 22.-Sectional View of One Cylinder Vertical Gas or Gasoline Engine Suitable for Automobile Repair Shop Power Plant.

Exhaust Valve Spring Washer

Exhaust Valve Lever

Valve Rod Head

Crankpin Brasses

Connecting Rod

Ignitor

Piston

[blocks in formation]
[ocr errors]

the electrical current is to be used for lighting as well as power it is, of course, necessary to provide an actual surplus over the power needed to run the shop in order to furnish the current for illumination.

As practically all automobile mechanics are familiar with the explosive motor, owing to its almost universal use as a prime

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]

Fig. 23.-Outlining Method of Installation of Stationary Gas or Gasoline Engine for Shop Power.

mover in automobiles, it is reasonable to expect that many isolated repair shop owners will avail themselves of the opportunity to use a source of power with which their workmen are thoroughly familiar. A one-cylinder vertical engine adapted for stationary power is shown in section at Fig. 22. Two large flywheels are used to insure steady running, and the power generated may be delivered to the shop line shaft by direct belt connection between the engine pulley and a corresponding member on the shaft. The

method of installing a horizontal engine adapted for stationary power and the provisions made for cooling the cylinder and disposal of the exhaust gases are so clearly shown in Fig. 23 that it is unnecessary to describe the installation further. For the very small shop using but few machine tools, it is not necessary to use the type of cooling system required by the larger powered engines, as the two or three horse-power necessary to operate a small lathe, drill press and emery grinder can be delivered economically from the simple hopper cooled engine, such as shown at Fig. 24.

FLYWHEELS

PULLEY

WATER HOPPER

BASE

Where a gas or gasoline engine is used for power, it is necessary to provide a substantial foundation composed of masonry and concrete as shown at Fig. 23, or of heavy timbers as shown at Fig. 22, in order to prevent excessive vibration of the floor. If possible, the engine bed should not rest on the floor, but the foundation should be carried down to solid earth. The smaller hopper cooled engine of two or three horse-power may be bolted directly to the shop floor, as these will not vibrate enough to be objectionable. A marked advantage of an isolated generating set such as shown at Fig. 20 is that it may be housed in a structure separate from the repair shop proper, reducing the first risk, whereas, where an engine is belted directly to the line shaft, it is usually in the same building as the machinery it drives.

Fig. 24.-Gas Engine Suited for Small
Repair Shop.

One of the important advantages accruing through the use of a gas or gasoline engine is in the economy of this form of power. If an engine is used capable of running on fuel oil instead of gasoline, there will be a marked saving, and the absolute limit in the low cost of power production will have been reached, the only forms of power showing to better advantage being those de

rived from natural sources, such as wind and water, neither of which can be applied universally. The table of power cost presented herewith shows the relative expense of various forms of power among which are included three forms of steam engines, the gas engine using manufactured or natural gas, the internal combustion motor using gasoline, the electric motor and the oil engine. Where the power requirements are not severe, the gas or gasoline engine in the smaller sizes will not prove so expensive to operate as to call for the use of an oil engine which is not as easily started or kept in operation as the forms burning gas derived from the various gas-producing methods or by the vaporization of volatile hydrocarbons, such as gasoline.

[blocks in formation]
« НазадПродовжити »